1. H UMAN FACTORS THAT AFFECT THE H YDROLOGICAL CYCLE AND D RAINAGE B ASIN SYSTEMS.

2. H UMAN FACTORS AFFECTING DRAINAGE BASINS AND HYDROLOGICAL CYCLE. Starter: Make a list of all the ways in which you think that humans can affect the hydrological cycle. 5 minutes – be ready to feedback.

3. F EEDBACK

4. H UMAN I MPACT WORKSHEET Complete the question on the sheet that you have been given.

5. A NSWERS Deforestation : Cutting down trees increases run-off, decreases evapo-transpiration (and therefore cloud formation) and leads to more extreme river flows as water is not intercepted and stored by the trees. (3 marks at least)

6. A NSWERS Irrigation: Taking water from a river or underground store can reduce river flow, lower water tables and increase evaporation/evapo-transpiration by placing water in surface stores (ditches/canals) or by crops removing water from the cycle as they grow.

7. A NSWERS Urbanisation: The removal of natural vegetation and replacement with impermeable surfaces and drains can speed up overland flow and evaporation and can lead to higher river levels. It also decreases the amount of water which returns to groundwater storage, possibly reducing the water table.

8. A NSWERS Mining: Breaking up of rocks leads to increased silting up of lakes, rivers and reservoirs leading to reduced storage capacity in these areas. Mining may also lead to reduced vegetation cover leading to increased run-off, higher evapo-transpiration and cloud formation altering the rainfall pattern.

9. A NSWERS Dam building: Greatly reduces and discharge of a river as storage is increased. Leads to increased evaporation and therefore can alter rainfall patterns.